cardiac glycosides

Question 1

cardiac glycosides:

1. what are they?
2. what are they derived from?
3. uses?
4. route?

Answer 1

1. digoxin
2. plants such as foxglove
3. slow down SVT and treat cardiac failure
4. -inhibit Na+/K+/ATPase pumps to keep sodium from exchanging for calcium. keeps calcium in the cell allowing for greater cardiac muscle contraction.
   - increases PNS activity d/t sensitizing of arterial baroreceptors and activation of vagal nuclei and nodose ganglion in the CNS (i.e. slow SA node transmission and prolong refractory period to increase time of conduction thru AV node).

Question 2

digoxin absorption:

1. P.O.:
2. IV:
3. protein binding:
4. excretion:
5. tissue reservior:

Answer 2

1. 75% absorbed within the first hour PO
2. theraputic plasma conc. achieved rapidly IV
3. 25% protein bound
4. excreted by kidneys at rate of 35%/day
5. principal inactive tissue reservior is skeletal muscle

Question 3

cardioglycosides

digoxin uses:

Answer 3

1. paroxysmal atrial tach (PAT), a-fib, a-flutter, heart failure